Phase-change media for high linear velocity and high recording density

Abstract

Overwrite characteristics have been studied for Ge-Sb-Te phase change media under high linear velocity conditions, ranging from 11.3 m/s to 22.6 m/s, with mark-edge-recording (MER). The Ge 1 Sb 4 Te 7 recording layer composition was chosen for the rapid cooling structure to obtain a sufficient erase ratio under high linear velocity conditions. The optical optimization for the disk structure and the narrow-grooved substrate have been applied to improve erase characteristics with MER. The optical phase-difference-reproduction (PDR) has been studied to realize a high carrier to noise ratio (C/N). The pulse-width-reduction (PWR) recording compensation has been developed for high recording density. A 44.8 dB C/N was obtained for 0.68 micrometers minimum recording mark length. A -26.8 dB erase ratio was obtained at 22.6 m/s linear velocity.